Makerspace Staff Guide: Equipment Maintenance

Wait! Before you replace the spoil board, see if you only need to resurface the board. Usually you can resurface the board once or twice before you need to replace it.

This spoil board is still usable. The cuts are very shallow and the board is still even.

This spoil board needs resurfacing. The cuts are getting somewhat deep and repeated cuts into it are leaving the top of the board uneven along the trenches.

This spoil board needs replacement. The trenches are far too deep to smooth out and the board has already been resurfaced at least once. The rabbit cut along the edge is also worn down to the point of not being visible.

There is not an exact measurement that can determine when the board needs to be replaced or resurfaced. When there users start to have difficultly finding areas to secure their material or if the board is noticeably uneven.

The lower right corner will always be more damaged than the rest due to it being the most common place to align materials. If possible, see if patrons can use another area to make the board last as long as possible.

If you need to replace the board

The CNC Spoil Board is a 0.75" MDF board pre-cut to a dimension close to 24x18. There may be a stock of pre-cut MDF boards available to use in the storage area by the lockers. If no boards are available, they will have to be purchased. Please do not store spoil boards in Make II as patrons often think it is scrap wood.

Purchasing pre-cut MDF boards - Home Depot has large sheets of 0.75" MDF that you can have cut to specific dimensions in store. Try to have at least two spare boards on hand at all times.

Resurfacing the board simply means taking off the top 1/16" of the board to smooth out damaged areas, leaving the top smooth and level.

In VCarve:

1. Set the workspace area of 24"x18".
2. Make a rectangle of the exact size and place it so that it fits in the workspace exactly.
3. Create a pocket toolpath with the following settings:
   • Start Depth: 0"
   • Cut Depth: 0.0625" (1/16")
   • Tools: 1/2" End Mill, with a spindle speed of 18000rpm and a feed rate of 3 inches/sec
   • Raster movement
4. Create a profile toolpath from the same rectangle with the same bit and settings, with the Machine Vectors set to 'On".

Now run the toolpaths in ShopBot 3, remembering to zero the X, Y, and Z axises.

Mark the center of the board with a pencil. Double-check your measurements as it is very important to have it centered properly. Place the new, blank spoil board on top of current board and secure it using clamps. Use caution when placing clamps - make sure they are not sticking out past the rails or in the way of travels, or new cut holes.

Open 01 Basic Deck Design Template.crv in VCarve. The file can be found on either the PPLD SharePoint drive here or in the My Documents folder of the CNC desktop.

Set the Job Dimensions to the exact size of the board and XY Datum Position (i.e. origin point) to the center. Note that the cut holes are placed in exact locations to align with the machine deck - you can move their position relative to the board as a whole (selected all together), but do not move individually or they will not line up. These should only be adjusted if you are moving the spoil board relative to the metal grid underneath, such as to leave more room for clamps. Normally you will not need to adjust these holes.

Cut the toolpaths in this order:

1. Counterbore - Everything should be preset, you just need to double check the selected bit and feeds/speeds. Export the toolpath and run it via the ShopBot 3 software.
2. Thru holes - Again, everything should be preset, you just need to double check the cut depth, selected bit and feeds/speeds. Export and run.

Clean off the top board and then remove from the machine. Set the board aside and put away the clamps. Remove old spoil board from deck by loosening and removing bolts with an allen wrench. Be sure to keep washers in place in the deck or the new board will not line up. 

Now place new spoil board on deck, lining up holes with washers. Some small adjustments to the washers might be needed to fit correctly. Insert bolts and tighten partially. Do not fully tighten until all of the bolts are in.

Now cut the following toolpaths:

1. Board level - pocket cut over entire surface area of board to level. Set the cut depth to 0.03125" (1/32") and use the 1/2" End Mill, running with a spindle speed of 18000rpm and a feed rate of 3 inches/second. Vacuum up the debris as needed with the ShopVac before continuing. If there are small sections along the edge that did not get properly cut, you can often just break it off with your hands. If not, redo the toolpath by either making the cutting area larger or adjusting the X/Y zero positions.
2.  Rabbit - profile cut along the sides and front (1/4" bit center of line for 1/8th cut into board with the Machine Vectors set to 'On') using the same bit and settings as the counterbore and thru holes. This is to provide a reference for machine true X,Y compared to placement of the spoil board as the board is not 100% straight compared to the machine. By default this uses a rectangular vector that runs along the edge of the board, but it is often easier to make a polyline that runs from approximately 1.5" from the back left corner and down, across the entire front of the board, and up to 1.5" from the back right corner.

Clean up - this is a good time to pull out the machine, blow out dust, wipe off machine, check rails and connections, and vacuum up any debris from hard to reach areas. The folded table in the corner of Make II is set to the same height as the CNC table, so you can simply slide it over.